Lysophosphatidic acid (LPA) is a bioactive lysophospholipid which exists in organisms in very small amounts and is produced and released when various cells including platelets are stimulated by bioactive substances such as cytokines (J. Biol. Chem. 270: 12949 (1995); J. Biol. Chem. 267: 10988 (1992)). Therefore, it is believed that LPA concentration is elevated at sites of inflammation, hemorrhage or the like. Actually, it has been clarified that 2 to 20 μM of LPA is contained in blood serum and, in the case of a model of intracerebral hemorrhage, the LPA concentration in cerebral spinal fluid has been reported to be elevated to about 3 μM (J. Neurochem. 67: 2300 (1996)). Recently, elevated LPA concentration in human arteriosclerotic lesions was also reported (Proc. Natl. Acad. Sci. USA 96: 6931 (1999)). Further, elevated LPA concentration has been reported in the ascites of patients with peritoneal disseminated ovarian carcinoma and in the blood of patients with multiple myeloma (Lipids 34: 17 (1999); Gynecol. Oncol. 98: 71 (364)). While a site of action of LPA had not been heretofore clarified, the receptor specific for LPA was recently identified (Biochem. Biophys. Res. Commun. 231: 619 (1997)) and various biological activities of LPA, for example, cell proliferation, migration/invasion and platelet aggregation, have been elucidated as being effected through a cell membrane receptor. Regarding cell proliferation promoting activity, the effect of LPA has been reported in, for example, smooth muscle cells (Am. J. Physiol. 267: C204 (1994); Atherosclerosis 130: 121 (1997)), renal mesangial cells (Clinical Sci. 96: 431 (1999)), stellate cells of liver (Biochem. Biophys. Res. Commun. 191: 675 (1998)), fibroblasts (Naunyn-Schmiedeberg's Arch Pharmacol 355: 1 (1997)), and various carcinoma cells and abnormal proliferation of these cells caused by LPA is suggested to be associated with disease progression. Futhermore, the acceleration of migration activity in monocytes (J. Biol. Chem. 270: 25549 (1995)), activation of NF-κB in fibroblast (J. Biol. Chem. 274: 3828 (1999)) enhancement of fibronectin-binding to the cell surface (J. Biol. Chem. 274: 27257 (1999); J. Biol. Chem. 268: 23850 (1993)), promoting invasion of carcinoma cells (Biochem. Biophys. Res. Commun. 193: 497 (1993)) and the like have been observed. Thus, the association with various inflammatory diseases and the invasion and metastasis of carcinomas are suggested. Further, LPA has been reported as a causative agent in neurite retraction and cell death in neural cells, in particular, the possibility of LPA to be associated with neurodestruction after hemorrhage (J. Neurochem. 61: 340 (1993); J. Neurochem. 70: 66 (1998)).
The search for an agent to inhibit LPA-induced cell activation is considered the key elements leading to the prevention and treatment of restenosis after percutaneous transluminal coronary angioplasty (PTCA), arteriosclerosis, artery obstructions, malignant and benign proliferative diseases, various inflammatory diseases, kidney diseases, proliferation of tumor cells, invasion and metastasis of carcinomas, cerebral or periphery nerve disorders and the like. There has been heretofore no report on a low molecular weight compound having such inhibitory activities.
The object of the present invention is to provide a novel azole compound having an excellent LPA receptor antagonistic action and the application thereof to medicines.